Flat-screen televisions are a major upgrade from existing cathode-ray tube TVs, making new high-definition sets one of the hottest-selling items in consumer electronics. But that dazzling picture and bigger screen come with a price: higher energy use.

To individual consumers, a bigger flat-screen TV might mean a noticeable bump in monthly electric bills. But at a national level, the onrush of these new energy-hungry TVs is a growing concern.

The move is significant because California's stringent efficiency standards in appliances have impacted codes across the country in the past. California's efficiency measures in big appliances, such as refrigerators, have been credited with keeping the per capita electricity consumption in the state steady since the 1970s.

But not everyone is happy with the California measure, which is expected to pass in November. Industry association the Consumer Electronics Association opposes the proposal, arguing that any efficiency improvements should come from consumer demand rather than regulation.

To unwind some of the issues around energy efficiency and TVs, we offer this FAQ, which draws on the analysis of CNET Reviews' senior editor David Katzmaier, who has been measuring power consumption in TVs for the past three years. You can see the latest data at CNET's Energy Efficiency Guide and power ratings of 150 HDTVs.

If I buy a new flat-screen TV, will I be slapped with a huge energy bill?
Not necessarily. The primary reason flat-screen TVs consume more power is because they are bigger. The California Energy Commission estimates that per square inch, LCDs consume a bit more than CRTs, but most people are also upgrading in size, which means significantly more electricity use. That's one reason why TV product ratings from the likes of CNET and Consumer Reports now include yearly energy consumption estimates.

Video: In this episode of The Green Show, CNET's David Katzmaier
explains the factors that affect TV power use. (He's introduced at
about 1:38 minutes in.)

From a technology point of view, LCD TVs in general are going to be more energy-efficient than plasma TVs of a comparable size. As one example, consider the Panasonic plasma TC-P54G1. Using a national average electricity cost of 11.5 cents per kilowatt-hour, that 54-inch TV will cost about $70 per year to run. By contrast, a 55-inch Vizio LCD model costs $31 a year to operate.

The third most important factor in energy consumption is the brightness. Obviously, the bright picture is one of the advantages of HDTVs over CRTs, but adjusting that down will not only cut energy use, it will also make your TV last longer.

So my bigger, brighter TV might cost me an extra $50 or $100 a year. What's the big deal?
For some households, spending more to power a new TV may not be a burden financially. But TVs--and electronics overall--are becoming a significant factor in home electricity bills and the national energy picture. This is why energy-efficiency standards have been developed for TVs, as they have already been done for industries that manufacture big home energy consumers, such as clothes washers and refrigerators.

The U.S. Environmental Protection Agency estimates that the country's 275 million TVs currently consume about 4 percent of households' electric use--or about enough to power all the homes in New York State for a year. In California, TVs are more like 10 percent of peoples' electric bills. With tens of millions of flat-screen TVs selling every quarter, those numbers are on the rise. At a global level, the International Energy Agency estimates the gadgets--cell phones, game consoles, and the like--already represent 15 percent of the electricity load. Right now, the most energy-hungry appliances are refrigerators, freezers, and clothes washers.

If electricity demand continues to go up, eventually utilities won't be able to keep up and will have to construct more power plants, which are expensive to build and cause more pollution. That's one reason why utility regulators in many states, including California, have established rules giving utilities incentives to reduce the electricity consumption of their customers.

In the case of TVs, California estimates that its efficiency codes would save households between $18 and $30 per year per television in electricity. After the existing stock of TVs is replaced, savings are on the order of 6.5 gigawatts hours, enough to power 864,000 homes. A large coal or nuclear power plant is about one gigawatt in size.

I hear that some flat-screen TVs consume as much electricity as a refrigerator. Is that true?
Yes, but remember size is what matters most. If you purchase a plasma TV with a 54-inch screen or bigger, electricity consumption while you're watching it could go as high as 600 watts, which is on par with your refrigerator. However, most TVs aren't running all day, so a refrigerator will consume more electricity in total.

The good news is that efficiency has been improving steadily over the past few years and there's a lot less variability among models. So LCDs with a similar-sized screen will have about the same energy consumption rating. That's also true, though to a lesser extent, for plasma TVs, according to CNET's Katzmaier.

Part of the efficiency increase can be traced back to EnergyStar. The program didn't rate TVs' power consumption in the "on" mode until late last year, but those rules have now been updated. More stringent version 4.0 standards are set to go into effect next May, which will mean that only about 25 percent of TVs will get the label, versus 80 percent right now. And those giant TVs are going to have a tougher time getting the EnergyStar label: TVs over 50 inches in size will have to meet the same power requirements--108 watts in the "on" mode--as TVs under that size in order to be EnergyStar compliant. The 5.0 EnergyStar specification, set to go into effect in May 2012, will represent a 65 percent efficiency improvement over today's models.

One benefit of the EnergyStar program now in place is that TVs' stand-by power--blamed for the vampire load in people's homes--is below one watt for almost all new models, CNET tests have found.

Ecos Consulting and the NRDC have developed a recommendation to the FTC on how TVs can be labeled on energy consumption.
Ecos Consulting, NRDC

So why the fuss with California's TV efficiency proposal?
EnergyStar is voluntary and the label is meant to show consumers that one product is more efficient than one without the seal. By contrast, the California Energy Commission's plan is a mandate that says TVs sold in the state after 2011 need to be 33 percent more efficient on average. In 2013, manufacturers need to make products 49 percent more efficient on average.

That approach has raised the hackles of the CEA, which says that setting an efficiency bar--equivalent to the Corporate Average Fuel Economy (CAFE) standard for autos--will "kill jobs and thwart innovation."

Those claims are discounted by regulators, efficiency advocates, and even some TV manufacturers.

The California Energy Commission notes that almost 850 models already meet the 2011 standard. Environmental advocacy group National Resources Defense Council estimates that almost 20 percent of today's models already meet the 2013 standard, according to NRDC senior scientist Noah Horowitz. Once in effect, the California standards will save the state $1 billion a year in electricity and prevent the need to build a 500-megawatt power plant, he said.

LCD TV maker Vizio publicly came out in support of the standard, saying in a letter to the California Energy Commission that "the incremental costs involved in achieving the greater energy efficiency are tempered by the unrelenting innovation in technology." (Click for PDF) The LCD TV Association, which uses its own GreenTV logo, has endorsed the plan (click for PDF).

Do TV manufacturers have the technology to improve efficiency?
Overall, yes. Some LCD manufacturers are starting to use LED-based backlights, rather than fluorescent backlights, to be more efficient. The added costs from this are projected to come down dramatically because they are on a "Moore's Law-type trajectory," said NRDC's Horowitz.

In general, plasmas don't have the same efficiency improvement potential as LCDs, according to Katzmaier. But at the Consumer Electronics Show this year, Panasonic--the largest plasma vendor--announced that it has developed technology to cut electricity by up to one half compared to 2007 models.

The proposed California standards are fairly lenient, which means that the majority of the TVs will be able to meet the standard without sacrificing image quality, Katzmaier said. The TVs most in danger of not meeting the California mandates or getting an EnergyStar label are the very large plasmas, particularly those that are more than 54 inches, he said.

Meanwhile, there is movement to ratchet down gadget use in other states.

I want to buy an energy-efficient TV. How do I find one?
When shopping around for HDTVs, seek out energy information in reviews and documentation. Screen size, technology, and brightness will be main factors in energy performance.

The EnergyStar standard coming next year should significantly narrow the field of compliant TVs and bring a 40 percent improvement over today's models. Even more detailed, standardized labels should be on the way as well. In 2007, the Federal Trade Commission was given authority to label electronics with efficiency ratings. If done well, consumers will have better tools to make energy efficiency a priority when shopping for electronics.

Updated September 24 at 2:05 p.m. PT with correction to measurement of potential electricity savings in California. Updated September 30 at 1:15 p.m. PT to note conditions for maximum energy consumption of large HDTVs.

About the author

Martin LaMonica is a senior writer covering green tech and cutting-edge technologies. He joined CNET in 2002 to cover enterprise IT and Web development and was previously executive editor of IT publication InfoWorld.
See full bio